Organisms Commons^™

The Effect Of Mtad On Eight Strains Of E. Faecalis In Contaminated Root Canals, Bradley M. Newberry

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this investigation was to determine the antimicrobial effect of Biopure MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) as a final irrigant on eight strains of Enterococcus faecalis (E. faecalis) in contaminated root canals of extracted human teeth. In addition, the Minimum Inhibitory Concentration (MIC) and Minimum Lethal Concentration (MLC) of MTAD were also measured on the same strains of bacteria. Two-hundred and forty extracted human teeth were instrumented using 1.3% NaOCl followed by 17% EDTA to remove the smear layer. The teeth were randomly contaminated with one of eight strains of E. …

A Pilot Study Testing A Proprietary Sealant For Plaque Reduction, Jennifer Rowland

Loma Linda University Electronic Theses, Dissertations & Projects

Enamel demineralization due to increased plaque accumulation is a well-recognized problem associated with fixed orthodontic appliances. The purpose of this study was to evaluate the efficacy of a proprietary product to be marketed by 3M Unitek for the reduction of plaque accumulation and thereby reduce enamel demineralization.

Sixty four bovine teeth were divided equally into an untreated control group and a group treated with the proprietary sealant product. Both groups were subsequently immersed in a Streptococcus mutans culture. Plaque deposits from each group were removed, suspended in trypticase soy broth, serially diluted, and plated on trypticase soy agar at 1, …

Cellular Responses In Escherichia Coli To Lethal And Sublethal Doses Of Ozone, Indira Ruth Komanapalli

Loma Linda University Electronic Theses, Dissertations & Projects

Ozone is a major component of photochemical smog. High levels of this pollutant, sufficient to affect human health are found in many urban areas worldwide. Though limited studies in humans are supported by extensive findings from animal experiments, a difficulty in interpreting the results of these experiments has lead to an ambiguity on the biochemical mechanism of ozone toxicity. To elucidate the mechanism by which ozone causes cell damage and eventual cell death we conducted a comprehensive study using Escherichia coli K-12 as a model.

Studies on the comparative inactivation of bacteriophage lambda (λ), Escherichia coli, and Candida albicans …

In Vitro Plaque Formation On Orthodontic Resin Sealants, Leland W. Pack

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to examine in vitro plaque formation on sealant coated enamel. The plaque growth on different types of sealants placed on enamel was compared to each other and to an unsealed enamel control. The antimicrobial properties of sealants were also studied.

Sealant coated bovine enamel disks were immersed in a S. mutans culture medium for four days. The amount of bacterial plaque formation was quantified by removing the deposit, suspending it in solution with subsequent serial dilution. Aliquots of the dilutions were then spread on blood agar plates and incubated for 48 hours. The number …

Development Of Periapical Lesions In Immunosuppressed Rats, Phillip A. Waterman Jr.

Loma Linda University Electronic Theses, Dissertations & Projects

The pathogenesis of periapical lesions is the interaction of the oral flora with the existing host defenses. The role of bacteria has been established in endodontic disease but the contribution of the host defenses in periapical lesion formation is less clear. The purpose of this study was to compare periapical lesion development in immunosuppressed rats with that in normal rats. Thirty-five, eight-week old Sprague-Dawley rats were equally divided into seven groups. Groups 1, 2, and 3 were given weekly injections of Cytoxan, an immunosuppressive agent. Groups 4, 5, and 6 received no immunosuppressive therapy. Group 7 served as a control, …

The Duration Of The Effect Of Different Carbohydrates On Neutrophilic Phagocytosis, Judy L. Reeser

Loma Linda University Electronic Theses, Dissertations & Projects

In order to determine the duration of the effect of glucose, fructose, sucrose, honey, starch, and orange juice on neutrophilic phagocytosis, 10 subjects underwent a complete series of carbohydrate tolerance tests. Blood samples were drawn at specific time periods following ingestion of 100 grams of each carbohydrate. Blood was then analyzed for glucose and phagocytic index (the mean number of bacteria engulfed per leukocyte); a red blood cell and white blood cell count and differential white cell count were done also on about 1/2 of the samples. In addition, 7 other subjects participated in a fasting study in which no …

Molecular Weight Determinations Of Some Salmonella Potsdam Bacteriophage Dna's, Winston H. Richards

Loma Linda University Electronic Theses, Dissertations & Projects

Two group A phages, P9c/2 and P4/2, were studied. Their density, sedimentation velocity, and biochemical properties were compared. Their densities were determined by density gradient centrifugation in 38.3% cesium chloride. Sedimentation velocity was used to determine their molecular weights. To accomplish this, the DNA of P9c/2 and P4/2 was labeled with tritium and T₂ DNA, labeled with ³²P, was used as a standard. The DNA of P9c/2 and P4/2 was separately mixed with T₂ DNA and centrifuged in a 0-15% sucrose gradient. The molecular weights were calculated using the formula D₂/D₁= (M_{2 …}